VULNERABILITY OF SHIELDED FUEL PIPES AND HEAT PIPES TO HYPERVELOCITY IMPACTS

The vulnerability of space qualified fuel pipes and heat pipes to hypervelocity impacts has been assessed. The equipment has been placed behind representative spacecraft structure walls and operated at simulated conditions (i. e. carrying pressurized water or N2 gas). Several failure modes have been investigated, of which perforation has emerged as the most critical. Ballistic limit curves for failure mode 'perforation' are presented and compared against the test results. Impact induced overpressure has been investigated. Impacts on structure walls at velocities below 7 km/s can generate highly inhomogeneous fragment clouds. When the equipment located behind the structure wall is laterally confined, the existing approach for determining the failure probability (perforation / no perforation limit) strongly underpredicts its vulnerability. An approach to deal with failure probability in this case is presented.